PRO-E simulation was used to determine: Dimensions of the craft (0.25 m). Total mass (1.5 kg) of the PVC structure Moment of inertia (0.025 kg.m2) . Propeller size (9 inch). The results obtained enabled us to select a suitable BLDC motor for the quad rotor.
BLDC motor - out runner (the outer shell spins) is used Specifications: Weight: 56g Voltage: 10V KV: 1200 RPM/V Max Efficiency Current: 15.5A Max Power out: 180W. Turnigy Bell 2409-18T An electronic speed controller (ESC) is used to control the speed of electric motors. It is a pulse-width modulation (PWM) controller
Two 2200mAh 3S 25C Lipo Packs and a separate battery used for electronic circuitry. Size: 9 x 5 Clockwise and Counter-Clockwise orientation.
dsPIC 30f5015 motor control series microcontroller for onboard computation. All calculations were done in fixed point (signed Q15.16) Capable of providing 4 simultaneous independent PWM’s dsPIC features, hardware multiplier, 16 bit architecture Operating with a clock multiplier to obtain 14MIPS.
User Base Station PC Transceiver(ground station) Quadrotor Transceiver Attitude Reference Motors PID Angle Gyroscopes Camera Translation (wireless) Estimate PID Magnetometer Pressure Sensor Correction Accelerometers Microcontroller
IMU data is corrupted and has to be filtered to make it usable. Gyro integration gives orientation but drifts over time.
Accelerometer gives the gravity vector. Integration of rate gyros gives attitude. Noise in gyros: Offset White noise Leads to drift The ‘g’ reference vector from the accelerometer is used to correct this drift
The gyro is integrated to give the roll and pitch. obtain the calculated ‘g’ vector. The error between the measured and calculated ‘g’ vector is adjusted into the gyro data.Gyroscope Roll/Pitch Compensation Integration(rad/unit time) angle Error PIDAccelerometer Estimated ‘g’ Cross Product(rad/unit time) vector
Two options for orientation estimation Kalman filter Complimentary filter The Complimentary Filter: does not require the system model is optimized for microcontroller implementation performance is comparable to the Kalman Filter
PID controller was used for roll and pitch control. Larger P leads to faster response, I used for reference tracking D dampens the oscillations, reduces overshoot A simulation was done using the mathematical model in MATLAB. The gains found were fine tuned on the actual system
Objective: Sensing translation in X- axis Sensing translation in Y- axis Yaw computation
Wireless camera over IP are very expensive. Camera of the smart phone was used for live streaming. Bluetooth link was used between the camera and the base station. A Red Cross of the ground was used as reference for determining the position of the craft.